Heretofore, ethylene oxide has been utilized as a sterilizing gas mixture and has been primarily used in a batch type process using a variety of sterilizing autoclaves into which the object or objects to be sterilized are placed. Moisture in the form of steam or water is then introduced in the evacuated autoclave followed by pressurization of the autoclave with the dry ethylene oxide gas mixtures. These processes all rely on gas mixing and diffusing to ensure uniform humidification of the sterilant.
One problem with utilizing autoclaves is that you do not always obtain uniform mixing of the gases. Another problem with utilizing autoclaves is that it is not readily adapted to be used for sterilizing a lot of different objects at different times. Another problem is that between each test, the pressure of the autoclave has to be reduced and the steam mixture of ethylene oxide and water has to be evacuated. Between each sterilization, the water carried in the bottom of the autoclave must be reheated to generate the steam for mixing with a new supply of ethylene oxide mixture.
To be an effective sterilant, ethylene oxide gas should be humidified to between 40% to 80% relative humidity throughout the system to be sterilized. Because of the many dead end cavities, tanks and long runs of small diameter tubing existing in an integrated system, continuous humidification of the ethylene oxide/Freon 12 mixture is necessary as the evacuated system is filled and pressurized to 20 to 22 p.s.i. with the sterilant. This ensures that all areas of the system are contacted with humidified sterilant.
Examples of apparatus and methods of controlling the relative humidity of gaseous sterilizers and sterilizing equipment are disclosed in United States Pat. Nos. 3,687,612, 3,791,424, 3,767,362, 3,620,265, 3,897,210 and 3,851,043.